This invention relates to paperboard cartons or containers of the clamshell type currently in vogue for packaging hamburgers and the like at fast food outlets. Such containers are characterized by a rectangular dish, bottom and a similarly shaped, inverted cover, the bottom and cover formed as a unit of either paperboard or a plastic material. The bottom and cover are usually integrally hinged together.
Standard clamshell cartons are formed from a flat blank into a hinge cover structure. The two cells that are created are attached at the hinge.
In order to form the clamshell, the hinge must be preformed before the carton is set up. There are three main basic methods now employed in this art. In the first, the blank is picked up by vacuum from the hopper. As the feed bar gate moves downward the hinge is broken by a cam action mounted on the feed bar. The blank with formed hinge is placed into the female cavity. In the second, the blank is picked up by vacuum and deposited onto the female forming frame. As the blank rests in the frame, folding blades are activated beneath the frame forming the hinge. In the third method, the blank is fed by vacuum and placed into a lug conveyor. The blank is then transported through a folding section where plows form the hinge. The blank with formed hinge is then conveyed and indexed into the female forming frame. Each of these methods limits the number of blanks that can be placed in a feed hopper.
Further, the conventional clamshell type carton has no handle structure and must accordingly be carried by the retail customer by squeezing it.